Although advertising and public relations services firms are located throughout the country, they are concentrated in the largest States and cities. California and New York together account for about 1 in 5 firms and more than 1 in 4 workers in the industry. Firms vary in size, ranging from one-person shops to international agencies employing thousands of workers. However, over half of all advertising and public relations establishments employ fewer than 20 employees.

The small size of the average advertising and public relations services firm demonstrates the opportunities for self-employment. It is relatively easy to open a small agency; in fact, many successful agencies began as one- or two-person operations.

Almost three-quarters percent of advertising and public relations employees are 25 to 54 years of age. Very few advertising and public relations services workers are below the age of 20, which reflects the need for postsecondary training or work experience.